You are right in that you don't pay for a 'job.' But you may pay for a service or invest in software, hosting, etc., if you are planning to build your own business.

Jobs are more along the lines of an hourly wage. You do so much work for so much pay.

I'm not familiar with jobs for mom, but maybe they are charging a membership fee for a service of matching you with potential employers. I suppose that is fair if that is realistically what they do.

Some of these sites really only give you a list of survey sites to join or other similar things that you can find for free if that is your intent. Quite often they also get paid by the survey sites, etc., when you sign up to them from the links they provide. (Not bad for them, eh?)

Again, I don't know if jobs for moms is like that or not. --- Actually I just went to look at it. If it's simply jobsformom dot com then it looks like a site just made for adsense clicks and not a legitimate service.

Jobs online are fine if you can find one and if you only want to make a few dollars an hour. The money stops when you stop.

Building an online business costs a little bit to get started (domain, hosting, etc.) and usually pays little or nothing at first, but then builds up to more and more income and less and less work.